DWM 1920 "n" suffix research (Polizei)

[sej-gun]

Dear Forum members.

I want to research the DWM 1920 (Police) Lugers whit the serial suffix letter “n”
DWM did probably not manufacture Luger’s whit this “n” suffix in that year of 1920?
Presumably only serial numbers whit “no suffix” and “a” “b” suffix.
Where did this “n” range came from?
My own 1920 “n” has a strange extra mark beside the serial number under the barrel, and also in front of the frame. It also looks like that someone has grinding on the camber, where the dated is stamped, and afterwards give it a new dated stamp (1920) and also a property stamp (double date)
If you haves one of this “unsolved” Lugers, I will be very happy if you will rapport
following points to my little research:

1) Serial number
2) Property date (1920/1920) (yes/no)
3) Sear safety (yes/no) or if it has been removed
4) Mag, safety (yes/no) or if it has been removed
5) Right Receiver Marks
6) Police unit marks
7) Other unusual marks

Photos will be fantastic also!

Everyone; please feel free to recite your opinion in this case about the “n” suffix range!!

I hope on your kindly cooperation

Reg. Jes